Gas turbine systems are widely utilized in fields such as power generation. A conventional gas turbine system includes a compressor, a combustor, and a turbine. During operation of the gas turbine system, various components in the system are subjected to high temperature flows, which can cause the components to fail. Since higher temperature flows generally result in increased performance, efficiency, and power output of the gas turbine system, the components that are subjected to high temperature flows must be cooled to allow the gas turbine system to operate at increased temperatures.
One gas turbine system component that should be cooled is the combustor liner. As high temperature flows caused by combustion of an air-fuel mix within the combustor are directed through the combustor, the high temperature flows heat the combustor liner, which could cause the combustor liner to fail. Specifically, the downstream end portion of the combustor liner may be connected to other components of the combustor, such as a transition piece, via a seal, and may thus not be exposed to various air flows that may cool the remainder of the combustor liner. Thus, the downstream end portion may be a life-limiting section of the combustor liner which may fail due to exposure to high temperature flows. Thus, in order to increase the life of the combustor liner, the downstream end portion must be cooled.
Various strategies are known in the art for cooling the downstream end portion of the combustor liner. For example, a portion of the air flow provided from the compressor through fuel nozzles into the combustor may be siphoned through an annular wrapper to channels defined in the outer surface of the downstream end portion of the combustor liner. As the air flow is directed through these channels, the air flow may cool the downstream end portion. However, cooling of the downstream end portion by the air flow within these channels is generally limited by the thickness of the downstream end portion, which reduces the proximity of the channels to the high temperature flows inside the combustor liner, thus reducing the cooling effectiveness of the channels. Further, cooling of the combustor liner through channels defined in the outer surface of the downstream end portion of the combustor liner generally results in comparatively low heat transfer rates and non-uniform combustor liner temperature profiles.
Thus, an improved cooling system for a combustor liner would be desired in the art. For example, a cooling system that provides relatively high heat transfer rates and relatively uniform temperature profiles in the downstream end portion of the combustor liner would be advantageous. Additionally, a cooling system for a combustor liner that reduces the amount of cooling flow required for cooling the combustor liner would be desired.